1. Field of the Invention
The present invention relates to a new form of ZSM-5, to a process for preparing it and to a method for using it in organic compound, e.g. hydrocarbon compound, conversion reactions. More particularly, it relates to making and using ZSM-5 which, in its as synthesized form, has different organic nitrogen-containing cations, extremely low sodium content and the same crystal structure as conventionally synthesized ZSM-5.
2. Summary of the Prior Art
Zeolite ZSM-5 is a relatively new zeolite which in its conventionally synthesized aluminosilicate form has the following composition expressed in terms of mole ratios of oxides in the anhydrous state: EQU 0.9 .+-. 0.2 M.sub.2/n O:Al.sub.2 O.sub.3 :xSiO.sub.2
wherein M is selected from the group consisting of a mixture of tetraalkylammonium cations, the alkyl groups of which contain 2-5 carbon atoms, and alkali metal cations, especially sodium and x is at least 5, said cations having the valence n. ZSM-5 has a distinctive X-ray diffraction pattern which further identifies it from other known zeolites. The original alkali metal cations of ZSM-5 can be exchanged by ion exchange with other ions to form species of the zeolite which have exceptional catalytic properties. Zeolite ZSM-5 and its conventional preparation are the subject of U.S. Pat. No. 3,702,886, the disclosure of which is incorporated herein by reference.